I. Field
The present disclosure relates generally to communication, and more specifically to techniques for supporting location services via a Home Node B (HNB) in a wireless network.
II. Background
HNBs are home base stations (sometimes referred to as femtocells or femto base stations) that are becoming increasingly popular and more widely deployed at various locations such as homes, offices, shops, apartments, etc. These HNBs typically serve as base stations for a wireless network operator (normally using licensed radio frequencies) and may be used to improve radio coverage, increase throughput, and/or provide other benefits for the network operator and/or users. Unlike macro base stations that are carefully deployed at specific locations and maintained by network operators, HNBs may be flexibly deployed in an unplanned manner at any location by users.
An HNB may support communication for one or more user equipments (UEs) within its coverage. It may be desirable to know the location of the HNB or a UE communicating with the HNB. For example, it may be necessary to know the location of the HNB in order to ensure that it is authorized to operate at its current location (e.g., is within a geographic area for which the associated network operator has a license to use the radio frequencies supported by the HNB). As another example, the user of a UE may place an emergency call using the UE. The location of the UE may then be determined and used to send emergency assistance to the user. There are many other scenarios in which knowledge of the location of the UE or the HNB is useful or necessary.
A device (e.g., an HNB or a UE) may have capability to autonomously determine its location without any assistance from a network. For example, the device may support standalone Global Navigation Satellite System (GNSS) and may be able to determine its location based on signals received from satellites in a GNSS. A location estimate obtained with standalone GNSS may have good accuracy. However, standalone GNSS may have some disadvantages such as a relatively long time to first fix (TTFF), inability to detect satellites with very low signal strength, etc. Hence, techniques that can improve performance over standalone GNSS for HNBs and UEs may be highly desirable.